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Azure Stream Analytics SU% Utilization keeps increasing RRS feed

  • Question

  • We've recently started using Azure Stream Analytics for data pass-through scenario's. The job has multiple outputs where one output is to a SQL server and another output is to a storage account. 

    After running the job for a couple of months i began to notice that my SU% increased by 10%. After some testing and investigating i found out that the event count didnt increase. So for some unknown reason the SU% keeps increasing. 

    Is this a known issue? Are other Azure Stream Analytics users running into the same problem? And if it is a known issue, is there a solution?


    Tuesday, January 7, 2020 7:11 AM

All replies

  • Hi Collin,

    You may observe a baseline SU % utilization with few or even without input events, because the system consumes certain amount of resource. The amount of resource consumed by the system may also fluctuate over time.

    Streaming Units (SUs) represent the resources and power to execute an Azure Stream Analytics job. SUs provide a way to describe the relative event processing capacity based on a blended measure of CPU, memory, and read and write rates. Each streaming unit corresponds to roughly 1MB/second of throughput. For details, Stream Analytics key concepts.

    The SU % Utilization metric is an indicator for the need to scale an Azure Stream Analytics job. High SU % Utilization may be a result of large window in a query, large events in input, large out of order tolerance window, or a combination of the above. Partitioning the query, or breaking down the query into more steps, and adding more SUs from the Scale tab are both strategies to avoid such a condition. For details, see Scale Azure Stream Analytics jobs.

    Ref - https://stackoverflow.com/a/31389980/10653466

    Tuesday, January 7, 2020 9:38 AM
  • In addition to what was mentioned by Chirag below do note that SU util is a combination of CPU and memory utilization. It could be impacted by sudden spike in ingress volumes, maintenance windows or sluggishness in the outputs / targets and such. 
    Tuesday, January 14, 2020 6:07 PM
  • Hi Collin,

    Just wanted to check - was the above suggestion helpful to you? If yes, please consider upvoting and/or marking it as answer. This would help other community members reading this thread.


    Tuesday, January 28, 2020 10:32 AM
  • Hi Colin,

    We haven't head back from you in quite some time - was the above suggestion helpful to you? If yes, please consider upvoting and/or marking it as answer. This would help other community members reading this thread.
    Monday, February 3, 2020 9:11 AM